Sunan Ibn Majah, Chapter: Chapters Regarding Funerals

"The Prophet (saw) used to seek refuge using the following words: 'Adhhibil-ba's, Rabbin-nas, washfi Antash-shafi, la shifa'a illa shifa'uka, shifa'an la yughadiru saqaman (Take away the affliction, O Lord of mankind, and grant healing, for You are the Healer and there is no healing that leaves no sickness).' When The Prophet (saw) fell sick with the sickness that would be his last, I took his hand and wiped it over his body and recited these words. He withdrew his hand from mine and said: 'O Allah, forgive me and let me meet the exalted companions (i.e., those who occupy high positions in Paradise).' Those were the last words of his that I heard." Sahih